DownsamplePointCloud

VTKEx/Cxx/PolyData/DownsamplePointCloud

Description

This example downsamples a point cloud by specifying the minimum distance two points can be from each other. The filter will delete points so that this criterion is met.

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

DownsamplePointCloud.cxx

#include <vtkSmartPointer.h>
#include <vtkPointSource.h>
#include <vtkPolyData.h>
#include <vtkCleanPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkPointSource> pointSource =
    vtkSmartPointer<vtkPointSource>::New();
  pointSource->SetNumberOfPoints(1000);
  pointSource->SetRadius(1.0);
  pointSource->Update();

  vtkSmartPointer<vtkCleanPolyData> cleanPolyData =
    vtkSmartPointer<vtkCleanPolyData>::New();
  cleanPolyData->SetInputConnection(pointSource->GetOutputPort());
  cleanPolyData->SetTolerance(0.1);
  cleanPolyData->Update();

  vtkSmartPointer<vtkPolyDataMapper> inputMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  inputMapper->SetInputConnection(pointSource->GetOutputPort());
  vtkSmartPointer<vtkActor> inputActor =
    vtkSmartPointer<vtkActor>::New();
  inputActor->SetMapper(inputMapper);

  vtkSmartPointer<vtkPolyDataMapper> cleanedMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  cleanedMapper->SetInputConnection(cleanPolyData->GetOutputPort());
  vtkSmartPointer<vtkActor> cleanedActor =
    vtkSmartPointer<vtkActor>::New();
  cleanedActor->SetMapper(cleanedMapper);

   // There will be one render window
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->SetSize(600, 300);

  // And one interactor
  vtkSmartPointer<vtkRenderWindowInteractor> interactor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);

  // Define viewport ranges
  // (xmin, ymin, xmax, ymax)
  double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
  double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

  // Setup both renderers
  vtkSmartPointer<vtkRenderer> leftRenderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(leftRenderer);
  leftRenderer->SetViewport(leftViewport);
  leftRenderer->SetBackground(.6, .5, .4);

  vtkSmartPointer<vtkRenderer> rightRenderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(rightRenderer);
  rightRenderer->SetViewport(rightViewport);
  rightRenderer->SetBackground(.4, .5, .6);

  leftRenderer->AddActor(inputActor);
  rightRenderer->AddActor(cleanedActor);

  leftRenderer->ResetCamera();
  rightRenderer->ResetCamera();

  renderWindow->Render();
  interactor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(DownsamplePointCloud)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkFiltersCore
  vtkvtkFiltersSources
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping DownsamplePointCloud: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(DownsamplePointCloud MACOSX_BUNDLE DownsamplePointCloud.cxx )
  target_link_libraries(DownsamplePointCloud PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(DownsamplePointCloud MACOSX_BUNDLE DownsamplePointCloud.cxx )
  target_link_libraries(DownsamplePointCloud PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS DownsamplePointCloud
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build DownsamplePointCloud

Click here to download DownsamplePointCloud and its CMakeLists.txt file. Once the tarball DownsamplePointCloud.tar has been downloaded and extracted,

cd DownsamplePointCloud/build

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./DownsamplePointCloud

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.